The present invention relates to a variable valve apparatus for varying the open/close timing or lift amount of engine valves in an internal combustion engine.
Japanese Laid-Open Patent Publication No. 2002-168105 discloses a variable valve apparatus for an automotive internal combustion engine, which includes a camshaft arranged on an exhaust side (referred to as “exhaust camshaft”), a fixed cam integrally mounted on the exhaust camshaft so as to drive an exhaust valve, a control shaft arranged on an intake side, a control cam fixed to the control shaft, a swing cam swingably mounted on the control shaft, a rocker arm swingably supported by the control cam, an eccentric drive cam integrally mounted on the exhaust camshaft and connected to the swing cam through the rocker arm and link members so as to drive an intake valve via the swing cam and an actuator for controlling the rotational phase of the control shaft (control cam) to change the operating position of the rocker arm and thereby vary the position of contact of the swing cam with a valve lifter of the intake valve. In this configuration, the variable valve apparatus is capable of varying the valve lift characteristics of the intake valve while reducing its height dimension for improvement in mountability.